[all-commits] [llvm/llvm-project] ce4ebc: [PowerPC] Remove support for SplitCSR.

[Sean Fertile via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: ce4ebc14a8963e58f08a6ab6c5ce4096469d570d
      https://github.com/llvm/llvm-project/commit/ce4ebc14a8963e58f08a6ab6c5ce4096469d570d
  Author: Sean Fertile <sd.fertile at gmail.com>
  Date:   2020-05-14 (Thu, 14 May 2020)

  Changed paths:
    M llvm/lib/Target/PowerPC/PPCCallingConv.td
    M llvm/lib/Target/PowerPC/PPCFastISel.cpp
    M llvm/lib/Target/PowerPC/PPCISelLowering.cpp
    M llvm/lib/Target/PowerPC/PPCISelLowering.h
    M llvm/lib/Target/PowerPC/PPCMachineFunctionInfo.h
    M llvm/lib/Target/PowerPC/PPCRegisterInfo.cpp
    M llvm/lib/Target/PowerPC/PPCRegisterInfo.h
    M llvm/test/CodeGen/PowerPC/cxx_tlscc64.ll

  Log Message:
  -----------
  [PowerPC] Remove support for SplitCSR.

SplitCSR was only suppored for functions with CXX_FAST_TLS calling
convention. Clang only emits that calling convention for Darwin which is
no longer supported by the PowerPC backend. Another IR producer could
use the calling convention, but considering the calling convention is
meant to be an optimization and the codegen for SplitCSR can be
attrocious on Power (see the modifed lit test) it is best to remove it
and codegen CXX_FAST_TLS same as the C calling convention.

Differential Revision: https://reviews.llvm.org/D79018